The core libraries and headers are released under the MIT license. Some modules are under LGPLv2 (see COPYING for details).
Upipe 0.5 (preview release 5) was released on February 2nd 2018. You can download the tarball from here (md5 b87a81fa34bd2dd039c7c3b31a8744de).
Development versions can be browsed and retrieved from the development site.